This invention involves certain novel dialkyl(N,N-dialkylcarbamoylmethyl) phosphine oxides which are useful as reagents for the fractionation of radionuclides (e.g., transplutonium elements) from nuclear process streams by solvent extraction (e.g., see U.S. Pat. No. 3,993,728 to Schultz) and/or for extracting uranium from wet process phosphoric acid (e.g., see U.S. Pat. No. 4,268,395 to Steward and U.S. Pat. No. 4,243,637 to Bradford and Ore). These novel phosphine oxides and others can be manufactured by the processes shown in copending application Ser. No. 239,731 filed Mar. 2, 1981, now U.S. Pat. No. 4,396,556, which is incorporated herein by reference. In general, these processes can make a phosphine oxide which can be represented by the general formula 1: ##STR1## where R1, R2, R3, R4, R5 and R6 are alkyl, aryl or hydrogen.
The following general equations represent a preferred process for making certain novel compounds: ##STR2## where PTC is a phase transfer catalyst.
In a preferred process, the alkylating reagent is stable in the presence of the base and the intermediate is converted rapidly to a desired product and not precipitated as a solid or converted to unwanted side products. Compounds of structure similar to those of this invention were, perhaps, implied by Siddall, Aqueous Reprocess Chem. Irradiated Fuels Sym., 57 (1964), and Siddall and Davis, J. Chem. Eng. Data, 10(3), 303 (1965). In these papers, no example of how to prepare any such compounds was given and there is no evidence that any such compounds have ever been prepared or characterized. The difficulties of preparation of such compounds by conventional routes is discussed in the Siddall and Davis publication. A solution of this problem is the novel synthetic method disclosed herein and in earlier filed application Ser. No. 239,731 filed Mar. 2, 1981.
The novel compounds of the present invention are useful as solvent extraction reagents for the removal or segregation of radionuclides from nuclear fuel or weapons process streams. Compounds of formula 1 were first reported by Zabusova, et al., Tr. Kazansk. Khim. Technol. Inst., (33), 167 (1964). Prepared were compounds of formula 1 where: R.sup.1 =R.sup.2 =C.sub.2 H.sub.5, R.sup.3 =R.sup.4 =H and R.sup.5 and R.sup.6 were as follows:
______________________________________ R.sup.5 R.sup.6 ______________________________________ H H C.sub.2 H.sub.5 C.sub.2 H.sub.5 C.sub.6 H.sub.5 C.sub.6 H.sub.5 H C.sub.4 H.sub.9 H C.sub.6 H.sub.5 CH.sub.2 H C.sub.6 H.sub.5 H p-CH.sub.3 C.sub.6 H.sub.5 ______________________________________
In subsequent publications (A. I. Razumov, et al., 5 ibid., 40(2), 212 (1969); A. I. Razumov, J. Gen. Chem. USSR (Engl. Transl.), 39(2), 235 (1969); A. I. Razumov, Khim. Primen. Fasforerg. Soedin, Tr. Konf. 4th 1969, 96 (1972) these authors screened these compounds for biological activity and examined them by spectroscopy. No mention is made of utility as solvent extractants for radionuclides and the compounds disclosed in those publications are not known to be useful for solvent extraction.
The July 13, 1981 Chemical and Engineering News (at page 51) notes that at the National A.C.S. Meeting, Industrial and Engineering Section, on Aug. 25, 1981, a paper will be presented on Extraction of Am(III) and Cm(III) from Synthetic High-Level Liquid Wastes Using Hexylphenyl-N,N-Diethylcarbamoylmethylphosphine Oxide and Hexylhexyl-N,N-Diethylcarbamoylmethylphosphonate by E. P. Horwitz, D. G. Kaline, L. Kaplan and G. W. Mason.